Multidirectional display system

ABSTRACT

An optical display system includes a projection system for outputting images having an image refresh frequency and a two-dimensional screen for receiving the images. The screen is coupled to a motion unit which allows a motion of the screen at a frequency which is equal to the refresh frequency of the images.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of European Application Number11185726.4 filed on Oct. 19, 2011, which is fully incorporated herein byreference.

BACKGROUND

It is known in the art to generate three dimensional images of objectswhich can be observed from all spatial orientations. However, adifferent view of the object is to be seen from different spatialorientations.

BRIEF SUMMARY

An optical display system includes a projection system for outputtingimages having an image refresh frequency and a two-dimensional screenfor receiving the images. The screen is coupled to a motion unit whichallows a motion of the screen at a frequency which is equal to therefresh frequency of the images.

An method includes outputting images from a projection system, whereinthe images have an image refresh frequency, and receiving the imagesusing a two-dimensional screen. The screen is coupled to a motion unitwhich allows a motion of the screen at a frequency which is equal to therefresh frequency of the images.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present invention together with the above-mentioned and otherobjects and advantages may best be understood from the followingdetailed description of the embodiments, but not restricted to theembodiments, wherein is shown in:

FIG. 1 is a longitudinal cut view of an example embodiment of an opticaldisplay system according to an embodiment of the invention;

FIG. 2 is a cross cut view through the system of FIG. 1 along lineII-II; and

FIG. 3 is an alternative arrangement of the example embodiment shown inFIG. 2.

In the drawings, like elements are referred to with equal referencenumerals. The drawings are merely schematic representations, notintended to portray specific parameters of the invention. Moreover, thedrawings are intended to depict only typical embodiments of theinvention and therefore should not be considered as limiting the scopeof the invention.

DETAILED DESCRIPTION

One or more embodiments of the invention relate to a display system and,more particularly, to a multidirectional display system.

It is an object of the invention to provide a display system which iseasy to use and employ and which requires simpler constituents.

This object is achieved by the features of the independent claim. Theother claims, the drawings and the specification disclose advantageousembodiments of the invention.

An optical display system is proposed, comprising a projection systemfor outputting images having an image refresh frequency; and atwo-dimensional screen for receiving the images, wherein the screen iscoupled to a motion unit which allows a motion of the screen at afrequency which is equal to the refresh frequency of the images.

Advantageously, a two-dimensional screen can be employed for generatinga multidirectional view, particularly of a video where video frames areupdated with a refresh frequency or a dynamic image being updated with arefresh frequency.

The screen displays a two dimensional view, e.g., an image or a videoframe. Advantageously, it is possible for a multitude of persons indifferent angular orientations with respect of the screen to observe thesame scenario on the screen. Particularly, people facing each other withthe screen arranged between them may nevertheless observe an identicalview on the screen with each one's individual field of view.

A typical refresh frequency of a video frame of an image on a pc monitoris 30 Hz, or 60 Hz. When the screen rotates with the refresh frequency,the image or frame will stay on the screen exactly the time of rotation,hence a person can see all images or frames. The velocity of the motionof the screen makes the flow of image or frame movements fluid for anobserver.

According to a favorable embodiment, the motion unit may provide arotational motion of the screen about an axis of rotation. Favorably,the moving screen can be created that can be located in e.g. the centerof a table and persons distributed 360° around the table can look at thescreen and see it as it is in front of them. When the screen rotateswith the refresh frequency, the image or frame will stay on the screenexactly the time of rotation, hence a person can see all images orframes.

According to a favorable embodiment, the motion unit may provide atilting motion of the screen about an axis tilting. When the screen istilted with the refresh frequency, the image or frame will stay on thescreen exactly the time of rotation, hence a person can see all imagesor frames in the angular range according to the reversal points of thetilt movement. For instance, a synchronous display of the image can beachieved at selected distinct angular positions with respect of thescreen.

According to a favorable embodiment, the projection system may comprisean optical direction unit which directs optical beams corresponding tothe images from an image source to the screen synchronous with therefresh frequency.

According to a favorable embodiment, a spatial orientation of theoptical beams may be stationary in respect of the screen. Particularly,the optical direction unit comprises a deflecting device for deflectingthe optical beams away from the optical axis synchronous with therefresh frequency. Preferably, the optical direction unit comprises areflecting device for directing the deflected optical beams towards thescreen synchronous with the refresh frequency.

According to a favorable embodiment, the deflecting device and thereflecting device may move synchronously in respect of one another. Thedevices can be arranged in a single optical constructional subassemblywhich facilitates the mounting of the system.

According to a favorable embodiment, the reflecting device may comprisea rotating mirror. The mirror may particularly have a plane reflectingsurface.

According to a favorable embodiment, moving parts of the opticaldirection unit may be stationary in respect of the screen.

According to a favorable embodiment, the axis may be collinear with anoptical axis of the projection system. The arrangement is easy to alignas desired.

According to a favorable embodiment, the screen may be enclosed in ahousing which is at least partially optically transparent. For instance,the housing may be a transparent cylinder that encloses the rotatingpanel. The actual image on the rotating screen can be observed throughthe housing. Because the frequency of rotation or tilting of the screenequals the refresh frequency of the dynamic image or video outputtedfrom the projection system and the optical direction device,respectively, a frame or image will stay on the screen the exact time ofrotation or tilting, so that all images or frames can be seen whenobserved from a particular location in the circumference of the housingand the screen.

According to a favorable embodiment, the images may be video frames. Itis possible to see video without any image processing from 360°. Theoptical direction system can project directly a normal video streamtowards the moving screen.

According to a favorable embodiment, an audio device may be coupled tothe system, e.g., to the screen or the projecting system or the like.Adding audio functionality to the system is technically simple and thisallows to output or input audio information. Expediently, the system canbe used in the field of unified collaboration and communication as videoand audio device. It can substitute traditional video systems in orderto have a system that can be put on a table so all attendees of ameeting can sit around the table and attend the meeting in front of eachother. An individual attendee can see the other attendees and observe atthe same time the screen displaying a video conference.

According to a favorable embodiment, the system may be implemented in atelevision set. It is possible to watch TV omnidirectionally without anyimage processing.

FIG. 1 depicts schematically in a longitudinal cut view an exampleembodiment of an optical display system 100 according to the inventionwhiles FIGS. 2 and 3 show a cross sectional view according to line II-IIin FIG. 1.

The optical display system 100 comprises a projection system 10 foroutputting images having an image refresh frequency and atwo-dimensional screen 50 for receiving the images. The screen 50 iscoupled to a motion unit 30 which allows a motion of the screen 50 at afrequency which is equal to the refresh frequency of the images. By wayof example, the images may be images displayed on a pc monitor, atelevision set or video frames.

The motion unit 30 provides a rotational motion of the screen 50 aboutan axis A50 of rotation. Alternatively, the motion unit 30 may provide aswiveling or tilting motion of the screen 50 about the axis A50.

The projection system 10 comprises an optical direction unit 18 whichdirects optical beams 20 corresponding to the images from an imagesource 12 to the screen 50 synchronous with the refresh frequency. Theimage source 12 may be a video projector, for instance.

An optical beam 20 is directed from the optical exit of the image source12 towards the screen 50. A spatial orientation of the optical beam 20is stationary in respect of the screen 50.

The optical direction unit 18 comprises a deflecting device 14 fordeflecting the optical beams 20 away from an optical axis A10 and areflecting device 16 for directing the deflected optical beams 20towards the screen 50 synchronous with the refresh frequency. Deflectingdevice 14 is preferably a lens which deflects the optical beam 20 byrefraction. The reflecting device 16 is preferably a mirror.

In one embodiment, the deflecting device 14 and the reflecting device 16are rotating about an optical axis A10 of the optical direction unit 18and the projecting system 10. The optical axis A10 is collinear with therotation/tilt axis A50 of the screen.

Deflecting device 14 and reflecting device 16 move synchronously inrespect of one another and with the same frequency as the screen.

In another embodiment, the reflection device 16 may be a stationaryreflector ring instead of a rotating reflection device 16.

All moving parts of the optical direction unit 18, i.e., the deflectingdevice 14 and/or the reflection device 16 are stationary in respect ofthe screen 50 as they move with the same frequency, synchronously withthe refresh frequency of the images. Particularly, the moving parts andthe screen 50 can be driven by the same motion unit 30. Of course,separate drive units can be provided for the components.

The screen 50 is enclosed in a housing 60 which is at least partiallyoptically transparent. By way of example, the housing is a transparentcylinder which protects the rotating screen 50.

An audio device 80 may be coupled to the system 100 (FIG. 3).

The optical display system 100 can be placed on a table 70 so thatpersons can observe the screen around the perimeter of the housing 60.

When the optical direction unit 18 (its optical refracting andreflecting devices 14, 16) rotates in unison with each other and thescreen 50 the two dimensional screen 50 can be used to generate aomnidirectional image, for instance for displaying a video. From anyperspective, the screen 50 appears as a traditional video which evendoes not change when an observer moves around the perimeter of thehousing 60 so that all observers see the same image on the screen 50. Incontradistinction to a traditional display, however, where everyobserver must sit on one side of a static display, the observers can beat any position around the central screen 50.

The two dimensional screen 50 and the moving/rotating parts of theoptical direction unit 18 rotate at a rate that matches the video framerate so that there is a new image each period of rotation in order toavoid any one observer seeing skipped or repeated frames. Typical rates,i.e. refresh frequencies, used in video projectors are 30 Hz or 60 Hz,for instance. The size of the screen 50 can be adapted to the tolerableinertia caused by the rotation or tilting movement, depending on thematerials and construction used for the system.

What is claimed is:
 1. An optical display system, comprising: aprojection system configured to output images, and a two-dimensionalscreen configured to receive the images, wherein the screen isconfigured to rotate at a frequency equal to a refresh frequency atwhich the projection system outputs the images, and the projectionsystem includes an optical direction unit configured to direct opticalbeams corresponding to the images to the screen synchronous with therefresh frequency, wherein moving portions of the optical direction unitare stationary relative to the screen.
 2. The system of claim 1, whereinthe optical direction unit includes a deflecting device configured todeflect the optical beams away from an optical axis synchronous with therefresh frequency.
 3. The system of claim 2, wherein the opticaldirection unit includes a reflecting device configured to direct thedeflected optical beam towards the screen synchronous with the refreshfrequency.
 4. The system of claim 3, wherein the reflecting deviceincludes a rotating mirror.
 5. The system of claim 1, wherein a spatialorientation of the optical beams is stationary relative to the screen.6. The system of claim 1, wherein an axis of rotation of the screen iscollinear with an optical axis of the projection system.
 7. A method,comprising: outputting images at a refreshing frequency using aprojection system; rotating a two-dimensional screen, configured toreceive the images, at a frequency equal to a refresh frequency at whichthe projection system outputs the images; and directing, using anoptical direction unit, optical beams corresponding to the images to thescreen synchronous with the refresh frequency, wherein moving portionsof the optical direction unit are stationary relative to the screen. 8.The method of claim 7, wherein deflecting the optical beams away from anoptical axis synchronous with the refresh frequency.
 9. The method ofclaim 8, wherein directing, using a reflecting device, the deflectedoptical beam towards the screen synchronous with the refresh frequency.10. The method of claim 9, wherein the reflecting device includes arotating mirror.
 11. The method of claim 7, wherein a spatialorientation of the optical beams is stationary relative to the screen.12. The method of claim 7, wherein an axis of rotation of the screen iscollinear with an optical axis of the projection system.